The following vendors either have online ordering, or list enough information online to make ordering decisions. Vendors are grouped by their primary types (Electronics, Motors, etc.) and most, if not all have been verified by one or more members of the site.
This list is a first take at creating a comprehensive list of vendors, it is a work in progress and will update regularly
These vendors sell electronic components, microcontroller boards, or related items.
|Sparkfun||http://sparkfun.com||Excellent supplier of Arduino, break-out boards, components, buttons, etc.|
|Adafruit Industries||http://adafruit.com||Excellent supplier of Arduino and Arduino kits|
|Mouser||http://mouser.com||Electronics component supplier, has everything under the sun|
|DigiKey||http://digikey.com||Like Mouser, large component supplier|
|Seeedstudio||http://www.seeedstudio.com||Hong Kong-based electronics supplier, makes variant of Arduino|
|LiquidWare||http://www.liquidware.com/||LCD Shields, Beagleboard hardware|
Excellent supplier of new stepper motors, including gearbox motors at low prices.
No online ordering, but prices, CAD files, etc. available online. Some motors may have long lead times.
|Sparkfun||http://sparkfun.com||Limited selection of steppers, carries easydriver|
|Pololu||http://pololu.com||Limited selection of steppers, carries several in-house drivers|
|ProBotix||http://probotix.com||Handful of models, carries in-house drivers|
|Gecko||http://www.geckodrive.com/||High-end stepper drivers|
|Pololu||http://pololu.com||Smaller DC motors, great selection of drivers|
|Servo City||http://servocity.com||Large selection of DC motors|
|Grainger||http://www.grainger.com||Larger (1/4 HP+) DC motors|
|Stock Drive Products||http://sdp-si.com||Lots of gears, belts, and small parts in both metric and emperial|
|VXB Bearings||http://vxb.com||Huge selection of bearings|
|McMaster-Carr||http://mcmaster.com||Large vendor of mechanical components, nearly everything under the sun|
|Misumi USA||http://us.misumi-ec.com||Great vendor of mechanicals, online design tools for custom parts (view in 3D), low prices for one-off custom pieces|
|Servo City||http://servocity.com||Lots of spur gears, hubs, shafting|
|8020, inc.||http://8020.net||Structural Extrusion, Connectors, Linear Bearings|
|DumpsterCNC||http://www.dumpstercnc.com||Inexpensive shaft couplers|